I think in general players prioritize event integrity over almost everything. (Competitive players at least — the ones who would be shown on stream.) Is it a disadvantage to not know your opponent's full deck list while they know all 60 of your cards? Unequivocally, yes.
Does it add value to the livestream if an exact list is discussed, rather than a generalized one? I'd say so. That's more compelling to me as a viewer, and if I was putting on a production I'd want to be reporting the best and most accurate information available.
@kazambolt do you have any thoughts on post-match interviews? If someone is playing an interesting tech and it pulls weight the showcased match, of course the interviewer should ask about it. They'd be remiss not to. In that case, most of the deck is shown on stream, and uniquenesses are highlighted. So it's like, why not show the full deck list? We just watched and talked about it.
Is part of the problem the timing of when the deck list is discussed? (Between rounds; players are free to tune in. You mentioned the monitors being off in London, but can't anyone still tune in on their phone?)
I think the sideboarding factor does make it much less detrimental for your deck to be public knowledge in Magic, and Pokemon really has no answer in that regard.
The most "fair" solution would be for all submitted deck lists to be available to all players at all times, but that's logistically crazy to think about right now, and it doesn't seem very fun to straight up know all your opponents' decks.
In the end, I think you just kind of suck it up as a player and roll with whatever TPCi wants to do in the name of growth. I do think for Top 8 Pokemon should distribute deck lists like Magic does because at that point, it's likely many of those players have been featured on stream and it makes sense to open up. Top 32? I'm not sure.